Decomposition of the Rotation Curves of Spiral Galaxies

Rotation curve of spiral galaxies manifests the distribution of surface mass density of spiral galaxies. In this paper the decomposition of the rotation curve of three spiral galaxies (NGC1365, NGC6946 and NGC5457) into a bulge, an exponential disk and Burkert dark halo respectively are presented. An addition contribution of local structure such as arms and bar can be included to suggest modified model. The results show that this modified model provides a good agreement with the observed rotation curve.